terry



A Patented Feb. 3,

UNITED STATES- A1,AfraN'I'- OFFICE CHARLES M. TERRY, or DECATUB, ILLINOIS, AssIGNoR 'ro A. w.. CASH coMPANY, yor

DEcA'rUR, ILLINOIS, A conronArIoN or DELAWARE y BEGULATING APPARATUS Appuoaaon mea February 2s, 192s. -seran m. 342,130.

This inventionrelates to a paratus for controlling the combustion of uel in a furnace and more particularly to apparatus connected to a combustion control device and 5 actuated in accordance with the pressure 1n the furnace boiler -to regulate the combustion and insure the maintenance of the boiler pressure within a desired operating range.

The invention is particularly useful in 1 controlling combustion in a steam boiler furnace', so that the changes in steam'pressure due to variations in the demand on the boiler may be utilized to vary the supply of fuel and air to the furnace. In this way, a slight drop in steam pressure will cause a sli ht increase in the rate of combustion, an a large drop in steam pressure will cause a cor-- respondingly large increase in the combustion rate. Various types of mechanisms have 0 been proposed to accomplish this purpose. but they have involved complicated cumbersome and expensive assemblies of fluid pressure operated apparatus, and there has been a recognized necessity for their simplification and the provision of a device which is made up of few parts and is so simple in its operation that it will not readily get out of order and will give a long life of useful'service.l

It is accordingly the main object of my invention to provide a simple and inexpensive apparatus which will cause a damper or other combustion control device to assume vdefinite positions in accordance with variations in the pressure in a furnaceboiler.

It is a further' object of my invention to provide an apparatus of this general t e' which can be easily and simply connecte to the devices which it controls without requiring complicated mechanical linkages.

With these and other objects in view, as will be ap arent to those skilled in the art my invention resides in the combination of parts set forth in the specification and cov? ered by the claim appended hereto.

In accordance with my invention, I pass a fluid under pressure through a reducing valve, and vary the adjustment of the rel ducing valve in accordance with variations in the pressure wit-hina boiler., The fluid pressure on the discharge side of the reducconnected to devices which serve to control.

the combustion in the boilerV furnace. Any

suitable fluid, such as city water, may be passed through the reducing valve,and it is immaterial if the lsupply ressure varies since the reducing valve wil automatically c compensate for this. A slight' leakage is perl I mitted continuously from the discharge side,-

of the valve so as to ensure satisfactory'operation thereof. p

Referring to the drawing illustrating one embodiment of my invention, the single iigure illustrates somewhat diagrammatically land partly in section an arrangement for controlling the position of a damper in accordance with' variations in the pressure in a steam header. v

The embodiment illustrated comprises a pipe 10 which is arranged to supply fluid under pressure from anysuitable source, such as the city water supply, to a reducing valve 11. The fluid` leaves the valve 11 at a reduced pressure through a pipe 12, and is allowed to flow through a ipe 11i` and partially open valve 15 to a rain, not shown. lThe' rate of flow, which is-not critical, is adjustable by means of valve 15, which may be of standard construction, and is simply maintained at a point which provides satisfactory operation of the'reducing valve.`

The pressure in pipe 12 is transmitted through a pipe 16 and branch'18 to a fluid pressure operated mechanism oomrlnisinga stationary cylinder 19, in which is ocated a slidable piston 20. The piston 20 is biased in one direction by meansl of a compression spring 22, which urges it against the fluid pressure and it will, therefore, beseen that within the limits for which-the ap aratus is designed the iston will take a pos1tion relative to the cy inder which is at all times proportionate to the luid'pressure in pipe 12, An increase in the fluid pressure will move the piston to the left and` thus compress the spring until the increased force due to the spring balances the increased fluid pressure. a constant discharge pressure regardless of In order to transmit mcernents of the iston to a device to be controlled, and to avold the use of intermediate relays or other complicated devices, I provide a simple mechanical connection comprising a piston rod 23'attached to the piston and extending outside the cylinder 19. I have shown the rod 23 connected by a link 24 to the arm 26 of a damper 27. This damper is arranged to control the fiow in a duct 28, which may be used to deliver air toI a furnace (not shown) or for various other purposes. It will be apparent that the damper 27, as shown, is merely typical of various 'combustion control devices which may be utilized, such as chronometer valves, rheostats, speed governor attachments, etc.,land the expression combustion control device used in the claim is to be interpreted broadly as covering` each of these equivalent constructions. The pipe 16may continue beyond the branch 18, as indicated, and may lead to other cylinders.(not shown) similar to cylinder 19, whereby any desired number ofdampersor other devices may be operated simultaneously. The spring 22 serves .to bias the piston 20 to move the damper 27 1n a direction to increase the rate of combustion of fuel in the furnace.

The reducing valve 11 comprises a cylindrical valve member 3() which is freely slidable vertically in a stationary sleeve 31 mounted. in the valve casing 32. The sleeve 31 provides a valve seat 34 integral therewith, and the valve ember 30 cooperates with the seat to control the fluid flow through the valve and the pressure on the discharge side of the valve. The sleeve 31 has port openings 35 therein to admit the fluid, and these openings are covered by a fine mesh screenr36 which prevents the entrance of foreign material.

A flexible diaphragm 40. preferably circular in shape, is arranged above the valve 30 and is connected thereto by a pin 41. This diaphragm is clamped between a fiange42 on the valve casing 32 and a flange 44 on a hollow cylindrical frame 45. lIt will thus be seen that the lower side of thediaphragm is sub- ]ected to the fiuidypressure on the discharge side of the valve. The fiuid on the discharge side of the valve is at a low pressure compared to that on the inlet side, and the arrangement is such that an increase in the low pressure will tend to close the valve. The

- valve 30 is urged upward against the` diaphragm by a small compression spring 46,

located within thve hollow valve member 30" and resting on the plug 47, and also by the pressure of the fluid on the inlet side of the valve, this fluidbeing free to enter beneath the valve 30 through a small port 48 therein.

The construction of the reducing valve as so far described is substantially the same as that shown in the patent to Cash No. 1,190,514, which discloses a valve intended to maintain stood that header 50 is connected to the furnace boiler.

.The header 50 is shown connected by a small pipe 51 to the pressure chamber 52 in thetop of the apparatus where the variable steam pressure is applied to the upper side of' a second flexible Adiaphragm 53 which is clamped between a'cap 54 and a flange 55 on the frame 45. The diaphragms 40 and 53 are connected by a rigid vertical rod 56 in such a manner that the pressure on each diaphragm opposes thev pressure on the other. The diaphragm 53 is preferably made with a much larger effective area than the diaphragm, 40, so that a small change in the steam pressure will cause a large change in the fluid discharge pressure. Because of' this iflerencc in area., and since the steam pressure is ordinarily much greater than the pressure obtainable or desirable on the discharge side of the reducing valve, it is usually necessary to provide additional means to counteract the pressure on diaphragm 53. In the embodiment illustrated, this means comprises a heavy compression spring 60 mounted beneath-the diaphragm 53 and surrounding the rod 56. The upper end of this spring bears against the pressure plate 61 in contact with the diaphragm, and the lower end of the spring is supported on a horizontal yoke 62 which extends through slots 64 in the frame 45. The yoke 62 is in turn supported onfnuts 65, which are threaded to studs 66 attached to the frame. By adjusting the'nuts 65, the spring pressure. can be varied as desired.

The operation of the apparatus will now be apparent from the above disclosure. City water or any other suitable fluid under pressure fiows from pipe l0 thorugh the reducing pressure on the'diaphragm 53 is at all times balanced by the pressure of spring 60 and the fluid pressure on the diaphragm 40. An 1ncrease in the steam pressure will cause the diaphragm 53 to move down slightly, thus opening valve 30 and increasing the fiuid pressure on the discharge side of the valve until a balanced condition again obtains. For every steam pressure within the limits of operation,

there will always be a definite and corresponding fluid pressure in pipe 12. However, because of the difference in the diaphragm areas, slight changes in steam pressure will cause magnified changes in the fluid discharge pressure. This variable fluid discharge pressure is applied to the spring loaded piston 20, which will assume positions corresponding to the different pressures,'and the damper 27 will move accordingly. The ow of fluid through the valve 15 is continuous, hence if the steam pressure in header 50 decreases, the piston 20 will move to the right and the iuid which is displaced by this piston movement is free to escape. By providingffor a continuous flow through'valve 15, rather than an intermittent discharge of fluid fromthe system, the operation of the device is stabilized, and the movements of the piston 2O are rendered smooth and gradual. p y

Since the connections between thefvario'us pieces yof apparatus are made bymeans of pipes instead of rods or cables, no limitation is placed on the arrangement, and the cylinders 19 may be located close to the dampers or other devices to'be controlled. The appara- `tus is simple and inexpensive to manufacture,

and is effective for the purpose intended.

Having thus described my invention, what I claimV as new and desire to secure by Letters Patent is r-f Apparatus for controlling the combustionin a furnace in accordance with variations in the pressure in the furnace boiler comprising a combustion control device, a iuid pressure operated mechanism directly connected t0 said device and biased to move it in one direc-'f tion to increase the rate of combustiotn, a casing having an inlet connected to a source of iuid under'high pressure and an outlet connected with said mechanism, a pressure reducing valve between the inlet and outlet providing a low pressure eiiective to actuate said mechanism in opposition to its bias, a diaphragm subjectedto said low pressure which is so connected to the valve as to tend to close the same when said low ressure increases, a pressure responsive device including a dlaphragm connected to the valve which is'subjected to the boiler pressure and tends to open the valve when the boiler pressure increases, and means providing a limited fiow of the low pressure Huid from the system, whereby said mechanism may move under its bias and increase the rate of combustion when the boiler @fessure decreases.

igned at Decatur, Illinois, this 19th day of February, 1929.

CHARLES M. TERRY. 

